Proper cleaning and disinfection of surfaces is essential to the health of patients and employees in sterile environments, such as hospitals, health clinics and dental offices, and of users of other public locations such as, for example, offices, schools, hotels, restaurants, airports, train stations and taxis, to name a few. In many situations, it may be difficult to ascertain after the fact whether one or more target areas of a surface has been cleaned. And while visual inspection provides an indication of the cleanliness of a surface, human eyes alone are not able to detect whether cleaning personnel actually cleaned or disinfected a surface. In addition, testing surfaces for the absence of dirt or organisms, is costly, requires specialized testing equipment, and often requires considerable time to perform. As such, a fast, simple, cost-effective method of determining whether one or more target areas of a surface have been cleaned would be helpful.